by Laurel Sterling, MA, RD, CDN
Calcium is required at every stage of life. It’s crucial starting in childhood when we really develop a solid foundation for healthy bones in the future. Throughout adolescence, bones grow rapidly. It’s also very important during pregnancy and lactation, as well as when one is healing from injuries. In later years, bones can begin to lose some of their sturdiness and strength, so a calcium-rich diet and supplementation become even more important. But with all of the options, it can be difficult to decide which type of calcium to take.
Some of the forms you’ll find on store shelves include: calcium carbonate, calcium citrate, calcium bis-glycinate, calcium citrate malate, calcium phosphate, calcium gluconate, calcium lactate, MCHC (microcrystalline hydroxyapatite), and others. Before choosing a type, there are several factors that need to be addressed. First, one should grasp the concept and importance of elemental calcium. Elemental calcium is the actual amount of calcium within the calcium supplement.
Looking at the differences between calcium carbonate and calcium citrate, there is more elemental calcium in calcium carbonate (40% elemental) than in calcium citrate (21%). A label may state 1,250 milligrams (mg) of calcium carbonate, which contains only 500 mg of elemental calcium. We can determine this because it is 40% elemental. This is important to note, because it can result in taking a lot of pills with the potential of absorbing little actual calcium into the blood stream.
Second, we need to look at solubility. Each form has a different degree of solubility and absorption. "Solubility” means the amount that can be dissolved in water at a neutral pH. If stomach acid levels are high, most forms of calcium are soluble. This is the case for most younger individuals, but as we grow older several issues can come into play (less stomach acid, acid-blockers) increasing the need for a more soluble form of calcium.
Third, it is important to remember that our body also needs other helper nutrients such as vitamin D, vitamin K, magnesium, and other minerals to better absorb any form of calcium. A more pH base intestine can interfere with calcium absorption, but vitamin D3, vitamin K2, and several other minerals increase intestinal absorption. All forms of calcium are absorbed best when taken with meals.
The Recommended Daily Allowance (RDA) for daily calcium is around 1,000 mg for adults, with upper limits ranging from 2,000-2,500 mg/d. This amount should be the daily total coming from a combined food and supplemental source. Calcium supplements are available in a variety of forms, including tablets, capsules, chews, liquids and powders. So whichever form of calcium you choose, remember that all varieties of calcium supplements are better absorbed when taken in small doses of 500 mg or less at a time, during mealtime.
The Daily Dose blog features health and wellness articles from Senior Nutritionist & Educator Jolie Root, LPN,LNC; Nutritionist & Educator Laurel Sterling, MA, RDN, CDN; and Featured Guest Blogger Karen Roth, MSNC. Other guest bloggers will also join us.